In recent years, electronic technology has developed remarkably, and the electronic-hydraulic control system shown in FIG. 5 has come to be adopted in the operation of cylinders for a work machine like a construction machine or the like in place of a mechanical or hydraulic lever control system.
In the conventional electronic-hydraulic control system shown in FIG. 5, the operation amount of an electric lever 101 which the operator manipulates is converted to an electrical signal and inputted to an electronic controller 102. The electronic controller 102 outputs a signal corresponding to the operation amount of the electrical lever 101 to the two end solenoids 103a and 103b of an electronic control hydraulic valve 103. The electronic control hydraulic valve 103 supplies a quantity of oil corresponding to the operation amount of the electric lever 101 to a hydraulic actuator 105 via hydraulic pipes 104a and 104b using a pump 106 so as to operate a rod 105a. According to this, fine control can be effected with simplified operation, and operation which is impossible by a mechanical and hydraulic operation is made possible.
However, although the conventional technology shown in FIG. 5 has the merit of electronic control, a problem exists in that the fatigue of the operator is extremely great in a case where the operation of two- or more-axle levers such as comb-off digging by a hydraulic power shovel or the like is performed. In addition, it is very difficult to vibrate a bucket while performing digging. That is, where comb-off digging is performed using a hydraulic power shovel, each work machine consisting of a boom, an arm and a bucket must be operated using hydraulic cylinders. Sediment must be dug out so that the surface of land becomes level or becomes a plane inclined at a given angle. To perform this work, the operator must operate each work machine while paying attention to the quantity of sediment in the bucket and the absolute angle (angle with respect to the digging plane) so as to be level. What is more, to compact the ground to be leveled, only a bucket, which is specifically one work machine, must be vibrated up and down at a predetermined amplitude and frequency. This work cannot be improved merely by the abovementioned conventional technique. Hence, it has been a problem to be able to obtain a uniform work result at any time without depending on the experience of the operator. Further, in the above-mentioned comb-off digging and ditch digging work, repeated digging must be performed up to a predetermined depth. Even in such simple repeated work, the operator himself must directly operate repeatedly, and therefore reducing the work in such a case has been a problem.
The present invention has been devised in light of the above-mentioned conventional problems. The first object of the present invention is to provide a work automation apparatus for hydraulic drive machines which are capable of performing repeated operations automatically. The second object of the present invention is to provide a work automation apparatus for hydraulic drive machines which is capable of reducing a correction operation by correcting an automatic operation through the intervention of a lever operation during automatic operation to make as much correction as the amount of the lever operation intervention and to play it back so as to start operation again at the correction position immediately preceding without starting at the initial position again during repeated automatic operation.